A gas turbine is formed of a compressor, a combustor, and a turbine. The compressor compresses air that has been taken from an air inlet to turn the air into compressed air of a high temperature and high pressure. The combustor supplies fuel to and combusts this compressed air to obtain combustion gas of a high temperature and high pressure. This combustion gas causes the turbine to be driven and causes a generator connected to this turbine to be driven. The combustion gas that causes the turbine to be driven is discharged as flue gas from a flue gas side of the turbine.
The gas turbine described above may reduce output because continuous use of the gas turbine causes contamination, deterioration, and the like. Due to this situation, abnormality in an operation state of the gas turbine has been monitored (for example, refer to Japanese Patent Application Laid-open No. 2007-192138), and characteristics of the gas turbine have been evaluated.
In the gas turbine described above, the surrounding environment may cause characteristics to be changed. For example, when an atmospheric temperature increases, a flow amount of air taken into the compressor is reduced. When a flow amount of air taken into the compressor is reduced, a supply amount of fuel to the compressed air needs to be reduced because there are limitations on a turbine inlet temperature. In this manner, output of the gas turbine is decreased. Thus, when a change in characteristics of the gas turbine due to contamination, deterioration, and the like is evaluated, influence of a change in characteristics caused by environmental conditions needs to be eliminated.
Conventionally, influence of a change in characteristics caused by environmental conditions has been reduced by preliminarily defining a correction value depending on environmental conditions, and correcting characteristics of a gas turbine, based on the correction value. However, the preliminarily defined correction value is not defined based on actual operation data, and there may be a gap between actual characteristics and characteristics of a gas turbine after correction based on the correction value. Thus, accuracy of an evaluation may be reduced.
In view of the foregoing, an object of the present invention is to provide a characteristic evaluation device for a gas turbine and a characteristic evaluation device for a gas turbine, which are capable of making a highly accurate evaluation.